Systemic Complement Activation Profiles in Nonexudative Age-Related Macular Degeneration: A Meta-Analysis

Area of Science:

• Ophthalmology
• Immunology
• Genetics

Background:

• Complement inhibition is a potential therapeutic strategy for age-related macular degeneration (AMD).
• Current understanding of complement pathway dysregulation in AMD and its relation to disease stage is unclear.
• Previous systematic review identified systemic complement activation profiles in early/intermediate AMD, geographic atrophy (GA), and controls.

Purpose of the Study:

• To meta-analyze existing data to quantify complement dysregulation in AMD.
• To determine if systemic complement activation or inhibition differs between AMD stages and controls.
• To provide mechanistic insights for future AMD clinical trials.

Main Methods:

• Systematic review and meta-analysis of seven studies including 710 participants and 23 effect sizes.
• Restricted maximum likelihood estimation was used to quantify complement dysregulation.
• Comparison of systemic complement activation and inhibition levels between early/intermediate nonexudative AMD, GA, and non-AMD controls.

Main Results:

• Patients with early/intermediate nonexudative AMD showed significantly higher systemic complement activation and lower complement inhibition compared to controls.
• No significant differences in systemic complement activation or inhibition were found in patients with GA compared to controls.
• Evidence supports systemic complement over-activation as a feature of early/intermediate nonexudative AMD, but not GA.

Conclusions:

• Systemic complement over-activation is associated with early/intermediate nonexudative AMD.
• Complement dysregulation patterns differ between early/intermediate AMD and GA.
• Findings support complement inhibition as a potential therapeutic strategy for early AMD.